1. A tungsten filament, radiating as a gray body, is heated to a temperature of 4000 R. At what wavelength is the emissive power maximum? What portion of the total emission lies within the...

1. A tungsten filament, radiating as a gray body, is heated to a temperature of 4000R. At what wavelength is the emissive power maximum? What portion of the total emission lies within the visible-light range, 0.3 to 0.75
m?

2. Determine the fraction of total energy emitted by a black body, which lies in the wavelength band between 0.8 and 5.0
m for surface temperatures of 500, 2000, 3000, and 4500 K.